Development of a KOH Defect Etching Furnace with Absolute In-Situ Temperature Measurement Capability

2005 ◽  
Vol 483-485 ◽  
pp. 283-286 ◽  
Author(s):  
Sakwe Aloysius Sakwe ◽  
Z.G. Herro ◽  
Peter J. Wellmann
Keyword(s):  
Calibration Curve ◽  
Temperature Sensor ◽  
Absolute Temperature ◽  
Temperature Measurements ◽  
Research Groups ◽  
Etch Pits ◽  
Measurement Capability ◽  
Etch Pit ◽  
Defect Characterisation

Etching temperature and time are important parameters in the etching of SiC single crystals in molten KOH for defect studies. However, comparison of results of different research groups is difficult because of the way temperature measurements are being carried out. Until now the temperature of the melt has been measured indirectly with a temperature sensor placed outside the melt on the outer walls of the crucible of the etching furnace, resulting in varying etching conditions for varying setup designs. In this paper we developed an etching furnace with the capability of measuring the absolute temperature in-situ directly in the KOH melt. A new thermoelement, resistant to hot molten KOH was developed. Temperature profile measurements of the molten KOH were carried out and a calibration curve of the furnace was obtained. Based on our temperature measurements, we found that etching at 530 °C for 5 minutes was optimal for defect characterisation, both for defect statistics and for distinguishing between the etch pit morphologies. At 550 °C the etch pits become too large, overlap each other and the etching is no longer defect selective.

Mechanically Aspirated Solar Radiation Shields: A CFD and Neural Network Design Analysis

2001 ◽  
Author(s):  
B. M. Fichera ◽  
R. L. Mahajan ◽  
T. W. Horst
Keyword(s):  
Neural Network ◽  
Solar Radiation ◽  
Temperature Sensor ◽  
Temperature Measurements ◽  
Analysis And Design ◽  
Computational Fluid Dynamics Analysis ◽  
Radiation Shields ◽  
Input Variables ◽  
The Relationship

Abstract Accurate air temperature measurements made by surface meteorological stations are demanded by climate research programs for various uses. Heating of the temperature sensor due to inadequate coupling with the environment can lead to significant errors. Therefore, accurate in-situ temperature measurements require shielding the sensor from exposure to direct and reflected solar radiation, while also allowing the sensor to be brought into contact with atmospheric air at the ambient temperature. The difficulty in designing a radiation shield for such a temperature sensor lies in satisfying these two conditions simultaneously. In this paper, we perform a computational fluid dynamics analysis of mechanically aspirated radiation shields (MARS) to study the effect of geometry, wind speed, and interplay of multiple heat transfer processes. Finally, an artificial neural network model is developed to learn the relationship between the temperature error and specified input variables. The model is then used to perform a sensitivity analysis and design optimization.

scholarly journals Sulfur bacteria promote dissolution of authigenic carbonates at marine methane seeps

2021 ◽  
Author(s):  
Dalton J. Leprich ◽  
Beverly E. Flood ◽  
Peter R. Schroedl ◽  
Elizabeth Ricci ◽  
Jeffery J. Marlow ◽  
...  
Keyword(s):  
Carbonate Rocks ◽  
Sulfur Oxidation ◽  
Methane Seeps ◽  
Etch Pits ◽  
Active Dissolution ◽  
Authigenic Carbonates ◽  
Sulfur Bacteria ◽  
Sulfur Oxidizing ◽  
Sulfur Oxidizing Bacteria

AbstractCarbonate rocks at marine methane seeps are commonly colonized by sulfur-oxidizing bacteria that co-occur with etch pits that suggest active dissolution. We show that sulfur-oxidizing bacteria are abundant on the surface of an exemplar seep carbonate collected from Del Mar East Methane Seep Field, USA. We then used bioreactors containing aragonite mineral coupons that simulate certain seep conditions to investigate plausible in situ rates of carbonate dissolution associated with sulfur-oxidizing bacteria. Bioreactors inoculated with a sulfur-oxidizing bacterial strain, Celeribacter baekdonensis LH4, growing on aragonite coupons induced dissolution rates in sulfidic, heterotrophic, and abiotic conditions of 1773.97 (±324.35), 152.81 (±123.27), and 272.99 (±249.96) μmol CaCO3 • cm−2 • yr−1, respectively. Steep gradients in pH were also measured within carbonate-attached biofilms using pH-sensitive fluorophores. Together, these results show that the production of acidic microenvironments in biofilms of sulfur-oxidizing bacteria are capable of dissolving carbonate rocks, even under well-buffered marine conditions. Our results support the hypothesis that authigenic carbonate rock dissolution driven by lithotrophic sulfur-oxidation constitutes a previously unknown carbon flux from the rock reservoir to the ocean and atmosphere.

Study on Mechanical Automation with Design of Rapid Milk Detector Based on Freezing Point

2013 ◽  
Vol 703 ◽  
pp. 282-286
Author(s):  
Ren Cai Zhang ◽  
Xiang Yu ◽  
Xing Ju Liu ◽  
Jin Hai Zhai ◽  
Zhen Wu Ning
Keyword(s):  
Integrated Circuit ◽  
Temperature Sensor ◽  
High Efficiency ◽  
Freezing Point ◽  
Electronic Control ◽  
Freezing Point Depression ◽  
Electronic Control System ◽  
Freezing Curve ◽  
Rack Mechanism

An efficient automated milk detector based on freezing point depression is designed. This detector shares characters of high efficiency and good stability with accuracy and automation. Its main parts include temperature sensor of IC (Integrated Circuit), pinion-rack mechanism and crank-rocker mechanism and electronic control system. Monitoring in-situ change of milk freezing curve and developing efficiency of sampling can be available by means of pinion-rack mechanism and IC temperature sensor mechatronics design. As a result, adulterating status of milk can be discriminated in a rapid and accurate and automated way. The detector may be employed to detect liquid foods other than milk as well.

scholarly journals Molecular biology approaches in bioadhesion research

2014 ◽  
Vol 5 ◽  
pp. 983-993 ◽  
Author(s):  
Marcelo Rodrigues ◽  
Birgit Lengerer ◽  
Thomas Ostermann ◽  
Peter Ladurner
Keyword(s):  
Molecular Biology ◽  
Biological Function ◽  
Molecular Approach ◽  
Research Groups ◽  
Blast Search ◽  
Search Facility ◽  
New Research ◽  
And Function ◽  
Functional Analyses

The use of molecular biology tools in the field of bioadhesion is still in its infancy. For new research groups who are considering taking a molecular approach, the techniques presented here are essential to unravelling the sequence of a gene, its expression and its biological function. Here we provide an outline for addressing adhesion-related genes in diverse organisms. We show how to gradually narrow down the number of candidate transcripts that are involved in adhesion by (1) generating a transcriptome and a differentially expressed cDNA list enriched for adhesion-related transcripts, (2) setting up a BLAST search facility, (3) perform an in situ hybridization screen, and (4) functional analyses of selected genes by using RNA interference knock-down. Furthermore, latest developments in genome-editing are presented as new tools to study gene function. By using this iterative multi-technologies approach, the identification, isolation, expression and function of adhesion-related genes can be studied in most organisms. These tools will improve our understanding of the diversity of molecules used for adhesion in different organisms and these findings will help to develop innovative bio-inspired adhesives.

scholarly journals Adenosine Triphosphate Measurement in Deep Sea Using a Microfluidic Device

Micromachines ◽  
2018 ◽  
Vol 9 (8) ◽  
pp. 370 ◽  
Author(s):  
Tatsuhiro Fukuba ◽  
Takuroh Noguchi ◽  
Kei Okamura ◽  
Teruo Fujii
Keyword(s):  
Adenosine Triphosphate ◽  
Microfluidic Device ◽  
Deep Sea ◽  
Temperature Sensor ◽  
Biochemical Parameter ◽  
Underwater Vehicle ◽  
Luciferase Assay ◽  
Bioluminescence Intensity

Total ATP (adenosine triphosphate) concentration is a useful biochemical parameter for detecting microbial biomass or biogeochemical activity anomalies in the natural environment. In this study, we describe the development and evaluation of a new version of in situ ATP analyzer improved for the continuous and quantitative determination of ATP in submarine environments. We integrated a transparent microfluidic device containing a microchannel for cell lysis and a channel for the bioluminescence L–L (luciferin–luciferase) assay with a miniature pumping unit and a photometry module for the measurement of the bioluminescence intensity. A heater and a temperature sensor were also included in the system to maintain an optimal temperature for the L–L reaction. In this study, the analyzer was evaluated in deep sea environments, reaching a depth of 200 m using a remotely operated underwater vehicle. We show that the ATP analyzer successfully operated in the deep-sea environment and accurately quantified total ATP within the concentration lower than 5 × 10−11 M.

Use of an FBG Sensor for In-situ Temperature Measurements of Gas Dielectric Barrier Discharges

2012 ◽  
Author(s):  
Meenu Ahlawat ◽  
Bachir Saoudi ◽  
Elton Soares de Lima Filho ◽  
Michael R. Wertheimer ◽  
Raman Kashyap
Keyword(s):  
Temperature Measurements ◽  
Dielectric Barrier Discharges ◽  
Dielectric Barrier ◽  
Fbg Sensor ◽  
Barrier Discharges

A CMOS Temperature Sensor with a Maximum Accuracy of 1.6 °C after One-Point Calibration

2013 ◽  
Vol 336-338 ◽  
pp. 216-220
Author(s):  
Chun Chi Chen ◽  
Keng Chih Liu ◽  
Shih Hao Lin
Keyword(s):  
Temperature Sensor ◽  
Pulse Generator ◽  
Circuit Complexity ◽  
Absolute Temperature ◽  
Cmos Process ◽  
Chip Area ◽  
Test Cost Reduction ◽  
Linear Delay ◽  
Time Amplifier ◽  
Fine Resolution

This paper presents a time-domain CMOS oscillator-based temperature sensor with one-point calibration for test cost reduction. Compared with the former CMOS sensors with linear delay lines, the proposed work composed of a temperature-to-pulse generator with adjustable time gain and a time-to-digital converter (TDC) can achieve lower circuit complexity and smaller area. A temperature-dependent oscillator for temperature sensing was used to generate the period width proportional to absolute temperature (PTAT). With the help of calibration circuit, an adjustable-gain time amplifier was adopted to dynamically adjust the amplified width that was converted by the TDC into the corresponding digital code. After calibration, the fluctuation of the sensor output with process variation can be greatly reduced. The maximum inaccuracy after one-point calibration for six package chips was 1.6 °C within a 0 80 °C temperature range. The proposed sensor fabricated in a 0.35-μm CMOS process occupied a chip area of merely 0.07 mm2, achieved a fine resolution of 0.047 °C/LSB, and consumed a low power of 25 μW@10 samples/s.

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